|
|
 |
|
|
Definition of Hansen's Disease (Leprosy)
Leprosy or Hansen's (han´senz)
disease is a chronic, mildly infectious malady
capable of producing, when untreated, various
deformities and disfigurements. It is caused
by the rod-shaped bacterium Mycobacterium leprae,
first described by G. Armauer Hansen, a Norwegian
physician, in 1873. The mode of transmission
is not fully understood. It is thought to be
transmitted by nasal discharges and skin sores,
possibly also by contaminated objects and arthropods.
Only 5% of those exposed acquire the disease.
The onset is intermittent and gradual; symptoms
may not appear until years after exposure. It
is seldom fatal, but its involvement of the
peripheral nerves destroys sensation and makes
the patient prone to inadvertent injury.
Types of Leprosy
There are two forms of leprosy. In the tuberculoid
form of the disease, the skin lesions appear
as light red or purplish spots. Tuberculoid
leprosy is the more benign type, even though
it is accompanied by nerve involvement, which
leads to numbness (usually of the extremities),
contractures, and ulceration. In lepromatous
leprosy, the skin lesions appear as yellow or
brown infiltrated nodules (protuberances) that
affect the mucous membranes of the eyes, nose,
and throat. There is a general thickening of
the skin, especially the face and ears. Lepromatous
leprosy is the more easily spread of the two.
Diagnosis and Treatment
Diagnosis is established when the bacterium
is isolated from the skin lesions or the mucous
membranes of the nose. Duration and treatment
of the disease depend upon its extent and character.
Patients with nodular lesions are more difficult
to treat and may succumb sooner; those with
the neural type of lesion, despite possible
mutilation and deformity, usually live longer
and even
experience spontaneous periods of subsidence
of the malady. Dapsone was the drug of choice
for leprosy from the 1940s until 1980, but due
to drug resistance and the necessity for long-term
(sometimes lifelong) treatment, it has been
replaced by a combination of drugs. This combination,
referred to as multiple drug therapy, has been
highly effective and requires a shorter treatment
period. The drug thalidomide has been approved
for use against a complication of leprosy called
erythema nodosum leprosum (ENL), which causes
fever, skin lesions, and other symptoms.
History and Incidence
Diseases that probably included the malady now
known as Hansen's disease are described as leprosy
in the Bible; segregation and disinfection were
advocated as methods of control (Lev. 13.14).
Leprosy is believed to have existed in Egypt
as long ago as 4000 BC and in India and Japan
earlier than 1000 BC. Infectious http://www.hrsa.gov/hansens
diseases from the East—all called leprosy—later
spread over most of Europe and the British Isles,
and the Crusades were a factor in disseminating
them still farther, so that by the 13th century
they had reached epidemic proportions. Leprosariums
were eventually established in most countries
for the care of those actually afflicted with
leprosy.
The disease still occurs in tropical and subtropical
countries of Asia, Africa, and Latin America,
especially where crowded and unsanitary conditions
contribute to its spread and even in the more
developed countries, it crops up from time to
time. In the United States, the disease is found
mostly in Louisiana, Texas, Florida, Hawaii,
as well as in California, the Northeast, and
other areas where immigrants from endemic areas
have settled. Although modern treatment is effective
against the disease, the number of cases in
the United States has increased significantly
since the 1960s. The World Health Organization
is working to eradicate the disease worldwide.
Source: Encyclopedia.com
(Not a U.S. Government Web site)
|
